HIERBA LOCA and TAGLLI (Pernettya furens and P. parvifolia) are two of about 25 species of Pernettya, mostly very small subshrubs that grow in the highlands from Mexico to Chile, the Galápagos and Falkland islands, Tasmania, and New Zealand. These plants belong to the heath family, Ericaceae, along with the cranberry, blueberry, Scotch heather, rhododendron, and trailing arbutus. Several species are known to be toxic to cattle and man, but only these two are known definitely to be employed as hallucinogens.
 
Pernettya furens, which in Chile is called hierba loca ("maddening plant") or huedhued, has fruits that, when eaten, can cause mental confusion, madness, and permanent insanity. The intoxication resembles that following the ingestion of Datura.

The fruit of tagili, of Ecuador, is well recognized as poisonous, capable of inducing hallucinations and other psychic alterations as well as affecting the motor nerves. Though the chemistry of these and other species of Pernettya needs further study, it seems that the toxicity may be due to andromedotoxin, a resinoid, or to arbutin, a glycoside. Both compounds are rather common in this plant family.